In the phrase gamtu-reul sseuda ("to wear a gamtu"), the gamtu was no metaphor — it was a real cap that people actually put on their heads. Woven from horsehair and worn under the wide-brimmed gat, it resembled the tanggeon headpiece. The word is said to have entered Korean from the Manchu kamtu, passing through the form gamto before settling as gamtu. What matters most is that not just anyone could wear one. Officials wore the gamtu as everyday dress, but commoners were not permitted to. So a person wearing a gamtu was, in effect, a person holding office. Over time the symbol of "official rank" came to overshadow the cap itself, and gamtu-reul sseuda hardened into the meaning "to take on an office or post."